Synthetic shake roofing is designed to replicate the look and feel of traditional wood shake but comes with advantages like greater durability and fewer maintenance demands. When it comes to re-covering an existing roof with synthetic shake, building codes generally require that the roof structure first be inspected to ensure it can support the additional weight of the synthetic material, especially if the previous roof was asphalt shingles or another lightweight system. Most codes allow one layer of roofing material to remain when adding a new synthetic shake roof, but two or more layers usually mean a complete tear-off before installing the synthetic shake. This helps avoid traps for moisture and weight issues that can cause structural stress or leaks. Simple diagnostics a homeowner can do include visually checking for sagging areas, inspecting attic access for signs of water damage, and confirming how many layers already exist on the roof surface.
While synthetic shakes are often treated for fire resistance, it's important to verify that the product you choose complies with local fire code requirements, especially in wildfire-prone areas. If you’re comfortable getting on the roof, a safe DIY check involves gently lifting a few existing shingles near a vent or flashing to gauge layer count and fastening method, but avoid walking on fragile sections to prevent damage. If the roof is older, has multiple layers, or if you notice any cracking or unevenness, it’s best to contact a professional roofer who knows local codes and manufacturer instructions well. When speaking to a contractor, ask “Does your installation method and the product you recommend meet our local building and fire codes for synthetic shakes?” and “Can you provide documentation showing the manufacturer’s warranty remains valid with this re-cover method?” This ensures your new roof will be both compliant and protected.